A microscope with a binocular tube is described in German Pat. No. 35 35 798 (WILD AG). The main objective of this microscope can be displaced until the optical axis of the objective coincides with the optical axis of one of the subsystems of the two optical system. Thus, the image quality in this subsystem is considerably improved.
However, the displacement of the objective disadvantageously results in the same object point being no longer imaged. In addition, the optical axis of objective and transillumination no longer coincide. Thus, a correcting movement is required to displace the observed object and optionally the illuminating device or even the complete microscope, including the objective.